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Expert-level detection of acute intracranial hemorrhage on head computed tomography using deep learning.
Computed tomography (CT) of the head is used worldwide to diagnose neurologic emergencies. However, expertise is required to interpret these scans, and even highly trained experts may miss subtle life-threatening findings. For head CT, a unique challenge is to identify, with perfect or near-perfect sensitivity and very high specificity, often small subtle abnormalities on a multislice cross-sectional (three-dimensional [3D]) imaging modality that is characterized by poor soft tissue contrast, low signal-to-noise using current low radiation-dose protocols, and a high incidence of artifacts. We trained a fully convolutional neural network with 4,396 head CT scans performed at the University of California at San Francisco and affiliated hospitals and compared the algorithm's performance to that of 4 American Board of Radiology (ABR) certified radiologists on an independent test set of 200 randomly selected head CT scans. Our algorithm demonstrated the highest accuracy to date for this clinical application, with a receiver operating characteristic (ROC) area under the curve (AUC) of 0.991 ± 0.006 for identification of examinations positive for acute intracranial hemorrhage, and also exceeded the performance of 2 of 4 radiologists. We demonstrate an end-to-end network that performs joint classification and segmentation with examination-level classification comparable to experts, in addition to robust localization of abnormalities, including some that are missed by radiologists, both of which are critically important elements for this application
Machine Learning Applications in Traumatic Brain Injury: A Spotlight on Mild TBI
Traumatic Brain Injury (TBI) poses a significant global public health
challenge, contributing to high morbidity and mortality rates and placing a
substantial economic burden on healthcare systems worldwide. The diagnosis of
TBI relies on clinical information along with Computed Tomography (CT) scans.
Addressing the multifaceted challenges posed by TBI has seen the development of
innovative, data-driven approaches, for this complex condition. Particularly
noteworthy is the prevalence of mild TBI (mTBI), which constitutes the majority
of TBI cases where conventional methods often fall short. As such, we review
the state-of-the-art Machine Learning (ML) techniques applied to clinical
information and CT scans in TBI, with a particular focus on mTBI. We categorize
ML applications based on their data sources, and there is a spectrum of ML
techniques used to date. Most of these techniques have primarily focused on
diagnosis, with relatively few attempts at predicting the prognosis. This
review may serve as a source of inspiration for future research studies aimed
at improving the diagnosis of TBI using data-driven approaches and standard
diagnostic data.Comment: The manuscript has 34 pages, 3 figures, and 4 table
Development and External Validation of a Deep Learning Algorithm to Identify and Localize Subarachnoid Hemorrhage on CT Scans
OBJECTIVE
In medical imaging, a limited number of trained deep learning algorithms have been externally validated and released publicly. We hypothesized that a deep learning algorithm can be trained to identify and localize subarachnoid haemorrhage (SAH) on head computed tomography (CT) scans, and that the trained model performs satisfactorily when tested using external and real-world data.
METHODS
We used non-contrast head CT images of patients admitted Helsinki University Hospital between 2012 and 2017. We manually segmented (i.e. delineated) SAH on 90 head CT scans, and used the segmented CT scans together with 22 negative (no SAH) control CT scans in training an open-source convolutional neural network (U-Net) to identify and localize SAH. We then tested the performance of the trained algorithm by using external datasets (137 SAH and 1242 control cases) collected in two foreign countries, and also by creating a dataset of consecutive emergency head CT scans (8 SAH and 511 control cases) performed during on call hours in 5 different domestic hospitals in September 2021. We assessed the algorithm's capability to identify SAH by calculating patient- and slice-level performance metrics, such as sensitivity and specificity.
RESULTS
In the external validation set of 1379 cases, the algorithm identified 136 out of 137 SAH cases correctly (sensitivity 99.3%, specificity 63.2%). Of the 49064 axial head CT slices, the algorithm identified and localized SAH in 1845 out of 2110 slices with SAH (sensitivity 87.4%, specificity 95.3%). Of 519 consecutive emergency head CT scans imaged in September 2021, the algorithm identified all 8 SAH cases correctly (sensitivity 100.0%, specificity 75.3%). The slice-level (27167 axial slices in total) sensitivity and specificity were 87.3% and 98.8%, as the algorithm identified and localized SAH in 58 out of 77 slices with SAH. The performance of the algorithm can be tested on through a webservice.
CONCLUSIONS
We show that the shared algorithm identifies SAH cases with a high sensitivity, and that the slice-level specificity is high. In addition to openly sharing a high-performing deep learning algorithm, our work presents infrequently used approaches in designing, training, testing and reporting deep learning algorithms developed for medical imaging diagnostics.
CLASSIFICATION OF EVIDENCE
This study provides Class III evidence a deep learning algorithm correctly identifies the presence of subarachnoid hemorrhage on CT scan
Cross-Modal Data Programming Enables Rapid Medical Machine Learning
Labeling training datasets has become a key barrier to building medical
machine learning models. One strategy is to generate training labels
programmatically, for example by applying natural language processing pipelines
to text reports associated with imaging studies. We propose cross-modal data
programming, which generalizes this intuitive strategy in a
theoretically-grounded way that enables simpler, clinician-driven input,
reduces required labeling time, and improves with additional unlabeled data. In
this approach, clinicians generate training labels for models defined over a
target modality (e.g. images or time series) by writing rules over an auxiliary
modality (e.g. text reports). The resulting technical challenge consists of
estimating the accuracies and correlations of these rules; we extend a recent
unsupervised generative modeling technique to handle this cross-modal setting
in a provably consistent way. Across four applications in radiography, computed
tomography, and electroencephalography, and using only several hours of
clinician time, our approach matches or exceeds the efficacy of
physician-months of hand-labeling with statistical significance, demonstrating
a fundamentally faster and more flexible way of building machine learning
models in medicine
PHE-SICH-CT-IDS: A Benchmark CT Image Dataset for Evaluation Semantic Segmentation, Object Detection and Radiomic Feature Extraction of Perihematomal Edema in Spontaneous Intracerebral Hemorrhage
Intracerebral hemorrhage is one of the diseases with the highest mortality
and poorest prognosis worldwide. Spontaneous intracerebral hemorrhage (SICH)
typically presents acutely, prompt and expedited radiological examination is
crucial for diagnosis, localization, and quantification of the hemorrhage.
Early detection and accurate segmentation of perihematomal edema (PHE) play a
critical role in guiding appropriate clinical intervention and enhancing
patient prognosis. However, the progress and assessment of computer-aided
diagnostic methods for PHE segmentation and detection face challenges due to
the scarcity of publicly accessible brain CT image datasets. This study
establishes a publicly available CT dataset named PHE-SICH-CT-IDS for
perihematomal edema in spontaneous intracerebral hemorrhage. The dataset
comprises 120 brain CT scans and 7,022 CT images, along with corresponding
medical information of the patients. To demonstrate its effectiveness,
classical algorithms for semantic segmentation, object detection, and radiomic
feature extraction are evaluated. The experimental results confirm the
suitability of PHE-SICH-CT-IDS for assessing the performance of segmentation,
detection and radiomic feature extraction methods. To the best of our
knowledge, this is the first publicly available dataset for PHE in SICH,
comprising various data formats suitable for applications across diverse
medical scenarios. We believe that PHE-SICH-CT-IDS will allure researchers to
explore novel algorithms, providing valuable support for clinicians and
patients in the clinical setting. PHE-SICH-CT-IDS is freely published for
non-commercial purpose at:
https://figshare.com/articles/dataset/PHE-SICH-CT-IDS/23957937
Development and External Validation of a Deep Learning Algorithm to Identify and Localize Subarachnoid Hemorrhage on Computed Tomography Scans
Diagnosing subarachnoid hemorrhages is commonly done through cranial computed tomography. Subarachnoid hemorrhages are associated with high mortality rates and a rapid and correct diagnosis is essential in the treatment of this disease. In midst of the recent advances in machine learning in neuroradiology, the Artificial Intelligence Team of the University Hospital Helsinki developed a convolutional neural network algorithm that can recognize and segment subarachnoid hemorrhages in axial slices of cranial computed tomography scans. The goal was to externally validate the convolutional neural network algorithm and assess its sensitivity and specificity
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